FIG. 1.

Recombinant pathways for degradation of 2-CB (top) and 4-CB (bottom), constructed by upgrading preexisting pathways for oxidation of (chloro)biphenyl, 4-HBA, catechol, and pentadiene with the aromatic ring dehalogenase genes ohbAB and fcbABC, respectively. Also shown are anaerobic dechlorination of Aroclors, which results in accumulation of predominantly ortho- and para-substituted CBs (left) (6, 34), and the bph-controlled metabolism of the 2-CB and 4-CB via, respectively, 2-CB-HOPDA and 4-CB-HOPDA (16, 31), which results in the production of CBAs and pentadiene.